Cardiac pacemakers provide an electrical stimulation of the heart when its own natural stimuli generation and/or conduction system fails to provide synchronized atrial and ventricular contractions at rates sufficient for a mammal's health. Furthermore, cardiac pacemakers may provide electrical overdrive stimulation to suppress or convert tachyarrhythmia.
Whereas most types of cardiac pacemakers comprise a pacemaker housing for an electronics package, which is implanted far from the heart, and a pacemaker lead which connects the housing with a pacing electrode, which is arranged within the heart, specific pacemakers have been developed, the housing of which is to be arranged in the heart. Such pacemakers are known as leadless pacemakers, as they do not require a pacing lead for connecting the electronics package to the pacing electrode. Instead, the pacing electrode is disposed on a distal portion of the housing. The leadless type pacemaker can solve typical problems with pacing leads, e.g., that they become a site of infection and morbidity or that they can become defective, thus deteriorating the pacemaker's performance or even blocking the delivery of pacing pulses at all.
Both in standard pacemaker arrangements and in leadless pacemakers, it is essential for their function to provide reliable and durable contact between the pacing electrode and the bodily tissue (e.g., heart tissue). Hence, for many years, considerable efforts have been made to develop suitable fixation mechanisms. Many such mechanisms, which are based on different fixation principles, have been implemented in commercial pacing lead configurations or leadless pacemakers, respectively. For example, a recent development regarding a leadless pacemaker with radial fixation mechanism is disclosed in U.S. Publication No. 2012/0158111.
The present disclosure is directed toward overcoming one or more of the above-identified problems.